Solar

How Do I Clean My Solar Panels?

Ready to finally clean your solar panels? Perhaps your solar panels are looking a little dusty? Perhaps they have an absurd amount of bird droppings? Or maybe it is spring cleaning time! Here is what you should know when it is time to give your panels a little scrub.

Do you need to clean? Depends on what you own.

First off, solar panels are self-cleaning! Generally, the rain should be enough to clean off any dirt that has accumulated on any of your Photo Voltaic (PV) panels. In most cases, cleaning your panels is not worth the hassle and danger. Regardless, over time you may find that a buildup of dust and particulates may occur. Here are some general guidelines for cleaning depending on what system you own.

Flat PV Panels

Google performed a case study in Mountain View, California showing that cleaned flat panels could produce up to 36% more energy compared to those that have not been cleaned. In this case, if you live in an area with a lot of pollution and particulates, it is a good idea to clean your panels when they become noticeably dirty.

Tilted PV Panels

The same Google case study found that clean tilted panels did not produce a significant increase in the amount of energy created compared to those that had not been cleaned. The rain is sufficient cleaning for these types of panels. Thus, in the case that you live in a dry climate without much rain,  you should consider cleaning.

Evacuated Tube Solar Collector

If you own this solar water heater, this system should be service cleaned. Do not attempt to clean it yourself! By attempting to clean this system yourself, you are tampering with pressure gauges and very hot water. It is best to leave this to trained professionals. If you have any questions regarding what type of panel you have, feel free to contact us, or a professional, before you start cleaning your solar panel.

Safety

It is important to keep safety a priority when cleaning. Please shut down your system before attempting to clean it. Clean in the morning or evening to avoid times when the solar panels can get very hot. Pick a day that is cooler in temperature, or overcast. If you feel uncomfortable climbing onto the roof, you may also seek professional cleaners.

Snow

When it snows, many people wonder if it is necessary to clean the snow off their photovoltaic panels. However, it is not necessary to be doing so. The glass panels are designed to be non-sticky, so most snow should slide off. Additionally, during heavy snowstorms, production will be low—it is part of the design of the solar panel system. So, there is no need to take any risks on a heavy snow day.

How to clean?

To avoid damaging the panel, do not use any types of soaps or cleaning fluids if possible. Soap can leave behind a residue and strong cleaning agents may cause damage to the glass. Use warm water and a non-abrasive cloth or sponge to tackle that dirty panel. Gently wipe down your panels. You may even spray with a hose on low pressure. If you find that there are stubborn stains or grimes that do not easily come off, then resort to a little dish soap or isopropyl alcohols. You may also look into purchasing rotary brushes that are specifically designed to clean solar panels and avoid scratching them. These are brushes and machines that professionals would use to clean your roof system.

 

Go solar today with enlighten.energy. Let’s Go Solar! Contact us if you have any additional questions.

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What are the advantages of net metering?

The benefits of net metering in solar energy:

Electricity bill savings

The greatest benefit of net metering for solar energy homeowners is that it can result in thousands of dollars saved over the lifetime of the solar panel system.

Shorter payback period

Thanks to the reduction of utility bills, homeowners can retrieve their investment costs much faster.

Reduction of the load on the utility

Power generated by the private households helps the utilities to reduce the stress on the electrical grid. Also, the produced energy is can also be used by the utility company clients in the neighbourhood which further decreases the demand for the energy production from the power plant perspective.

Virtual energy storage

For solar energy homeowners, the net metering becomes a way to store the produced energy surplus in the grid which becomes a kind of energy storage without a need to have a physical storage like a expensive high capacity battery at home.

Check out our other article on how net metering works.

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Why do we use solar panels?

Free and infinite energy

Solar energy is a renewable energy source which means that it is infinite compared to fossil fuels like propane, oil, coal, etc. The energy generated by the sun is enormous. The sun's surface is around 1.5 quadrillion acres. It only takes around 50 acres of the sun's surface to generate the equivalent of Earth's yearly energy consumption. A solar electric installation once set will generate free energy for many years and a return on the investment in 7 to 8 years.

How much energy gets to the Earth's surface?

Energy from the sun is transferred to the Earth's surface via radiation and just before it gets to us it is diffused in the atmosphere. Depending on the location, the power we can get at noon is around 320 kBTU/hr/sqft (or 1000 W/m2).

Solar panel efficiency

Unfortunately, we are not able to use solar power as a whole. We are limited with solar panel efficiency. Most of the PV modules used have a maximum efficiency of around 20%, which means usable power at noon is around 64 kBTU/hr/sqft (or 200W/m2). That is why standard 60 cell solar modules are around 300 W - 340 W.

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What size system do I need for my house?

Solar electric system size is measured in kWp (kilowatt in peak) because their energy output is not the same throughout the year. To estimate your system size you can divide your yearly utility bill by kWh/kWp coefficient.

Values of kWh/kWp coefficient vary based on the location. If you want to find out what is the value for your area check Global Solar Atlas map. Open the map and legend at the bottom right corner to estimate kWh/kWp coefficient value for your house. To achieve maximum performance of your system sign up with us and we will match you with the right professional installer company.

An Example:

For NY State we estimated 1,300 kWh/kWp and annual bill of 5,000 kWh. Your estimated system size will be 5,000 kWh / 1,300 kWh/kWp =  3.85 kWp.

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How does passive solar energy work?

Solar energy does not only generate electricity but it also can be used for passive heating. Using solar energy for passive heating is a very economical solution because it minimizes energy use. A passive solar building uses the movement of the sun throughout the day (considering seasonal changes in sunlight) to heat houses. The most important factors in passive solar design are windows by which the sunlight can pass through, absorbers which keep the warmth and the distribution of heat circulation. There are different requirements for different locations. For example in the northern hemisphere windows should be oriented south, while in the southern hemisphere windows oriented north are ideal. The disadvantage of a passive building is that if a house was not originally built in this technology, the renovation cost would be expensive. Even then, there is still the possibility to take steps that minimize the wasting of passive solar energy and minimize your long-term costs. It is possible to use a solar heating system such as solar collectors, which can be used for hot water or even as a source of house heating. The other option for using solar energy is electricity generated with photovoltaic (PV) panels, which can be used together with solar collector systems.

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How to install a solar water pump?

Pumps that work with solar panels are the same as every other pump. There is, however, a difference in the source of power. The installation of the solar pumping system is different for every type of kit.

  1. In general, the first step of installing a solar water pump is setting up the solar panel mounting and solar panels facing towards the sun. Make sure there is no shadow during the day on the solar panels.
  2. The next step is mounting the water pump to the water installation (water piping), and placing it stable underwater. Make sure, that nothing limits the water flow into the pump because it would reduce the pump's power. All running pumps that do not have a suction nozzle need to always be underwater because pumping the air can damage the pump.
  3. The last step is connecting all of the electrical connections.

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What is an off-grid solar system?

An off-grid solar system is a photovoltaic system that is not connected to the electrical grid. The system can generate and store energy on its own and provides it for further use by the consumer. As it is not connected to the grid, the energy generated by the solar panels needs to be stored to provide electricity to the user at all times (even at night when photovoltaic modules do not generate any energy).

The most basic components of an off-grid solar system:

Electricity generator

The role of the electricity generator in an off-grid solar system is fulfilled by the solar panels, which can generate electricity from the Sun.

Charging & discharging controller

In order to prevent the battery from overcharging and over-discharging, a solar controller must be used. It controls the charging voltage of the batteries, battery level and the voltage and current parameters of the solar panels so that they can provide the maximum power output that is possible.

Energy storage

The most common energy storage solutions consist of battery packs (mainly Lithium-Ion, Lead Acid or Gel batteries). They are used to store the energy generated by the solar panels to use it when solar panels do not generate enough of it.

Load

All of the electrical appliances that use electricity in the system are called load. Load is also referred to as the sum of energy that is consumed by the appliances.

Inverter

An inverter is used in off-grid systems that require AC Voltage output. It converts DC voltage to AC voltage which then can be used in houses in the same way as the grid electricity. They are most commonly used in households or summer cabins, where electricity is provided to the electrical sockets in the form of AC voltage. In off-grid systems that run solely on DC voltage (e. g. solar lighting systems) an inverter is not necessary.

Energy meters

An energy meter might be added to the system to measure the energy consumption of the system. It is not an obligatory component in off-grid systems.

Why off-grid solar systems?

Off-grid solar systems are commonly used in solar lighting or solar pumping locations where it is difficult or inconvenient to run an AC power cable to. They are a great source of power for sign lighting, as they generate and store enough energy to enable lights to operate at night without inconvenient cable connections.

These systems are perfect for homeowners that live in remote areas and the grid is far away from their households. Everyone can generate electricity on their own without having to connect the house to the electrical grid, which in some cases might not be possible. They are commonly used in summer cabins, as it is easier and more cost-efficient than connecting the cabins to the electrical grid.

They make a phenomenal solution for campers, yachts and other means of transport that need electricity but are mobile, and connecting them to the grid would be difficult. Solar panels are even used on the International Space Station, space rovers, and space shuttles as they can generate power in space or on other planets!

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What to do with old solar panels?

The global growth of solar energy over the past decade has made the photovoltaic industry one of the main pillars of the ongoing energy transition. More and more people are deciding to install their own PV system. Although solar panels are devices with long “expiration dates” (25-30 years), sooner or later they will need to be rid of. By 2050, the International Renewable Energy Agency projects that up to 78 million metric tons of solar panels will have reached the end of their life and that the world will be generating about 6 million metric tons of new solar waste annually.

Solar panels cannot be treated as ordinary waste and simply "thrown away". This is because of their size (it is a waste of large dimensions) and the varying materials they are made of. The main contributor to the total weight of a typical crystalline silicon PV module is glass (75%), followed by polymer (10%), aluminium (8%), silicon (5%), copper (1%) and small amounts of silver, tin, lead, and other metals and components. Therefore, in accordance with the law, they have to be collected selectively and transferred to a specialized recycling facility.

Who is responsible for reprocessing?

Some PV panel manufacturers offer a guarantee of collection and disposable services when the products wear out. However, it is important to be aware of the fact that the cost of these activities falls on the owner of the installation - either when purchasing the panels or when taking them to a recycling facility.

Recycling - the future of photovoltaics

Although the recycling of panels is a very complex and complicated process, there are already technological solutions that allow the recovery of the vast majority of raw materials used for the production of modules. Some of them even reach an astonishing 96% recycling efficiency, but the aim is to raise the bar higher in the future. According to the International Renewable Energy Agency (IRENA), raw materials recovered through recycling processes could be worth more than $450 million in total by 2030. This is equivalent to the number of raw materials currently needed to produce about 60 million new panels.

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How to connect solar inverter to grid?

What is a grid-tied solar electric system?

Solar electric systems can be divided into two categories:

  • Off-grid (not connected to the power grid and uses batteries to store generated energy)
  • On-grid or grid-tied (connected to the power grid where excess energy is transferred)

In this article, we will describe how can grid-tied systems be connected to the grid.

The 120% rule

When it comes to designing a solar PV system for any residential property, the 120% rule is used to determine the limit of how much new power generation the site’s electrical infrastructure can safely handle.

This rule is based on Main Breaker and Bus Bar ratings.

The calculation to determine the limit is maximum electrical equipment load which is Main Breaker Rating x 120%

An image of a regular domestic distribution panel

How big of a solar breaker can I install at my house?

If your service is 200 A:

200 A x 120% = 240 A - maximum load

This means that the solar breaker is limited to 40 A because the Main Breaker Rating + Solar Breaker must be less than or equal to 240 A.

Examples:

200 A + 40 A = 240A

200 A + 30 A < 240 A

The Main breaker is usually installed at the main electricity line going into your home.

If your service is 100 A:

100 A x 120% = 120 A - maximum load

This means that the solar breaker is limited to 20 A because the Main Breaker Rating + Solar Breaker must be less than or equal to 120 A.

Examples:

100 A + 20 A = 120A

100 A + 10 A < 120 A

The Bus bar is the part of the distribution panel where you install breakers.

What if I want to install a bigger system?

If your system amperage exceeds the 120% rule, don't worry! You can still tie your system to the grid using piercing lugs (or inline lugs). They are used to manually connect PV supply wires with electricity supply wires.

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Solar electric modules life span

Will my solar panels generate electricity forever?

The quick answer to this question is unfortunately no. The typical manufacturer guaranteed solar panel life span is between 25 and 30 years. However, this does not mean that they will stop producing after this time. The majority of solar panels after a period of 25 years produce at least 80% of their rated output power.

Solar energy is great, but how long will my solar panels last?

Solar module manufacturers usually ensure us that their product will last for 25 - 30 years with specific efficiency over this period. Every year, module efficiency slightly decreases. This decrease is otherwise known as the degradation rate. Typical degradation rate values vary from 0.8% per year for regular PV modules to 0.3% per year for premium manufactured modules. According to the NREL analysis paper, around 80% of solar modules last longer than warranty states.

Manufacturers performance warranty

Solar PV module manufacturers will certainly show guaranteed performance over the years on the product datasheet.

Example from one of Trina Solar products.

What can I do to make my solar panels last longer?

Solar electric systems usually require little or no maintenance. PV modules are designed to withstand snow loads and are resistant to weather conditions (wind, rain and even hail). The most important part to keep your system in good shape for a long time is to hire an experienced installer.

To reduce solar module degradation you can:

  • Check and clean your installation from debris or other possibly damaging objects
  • Hire a professional installer to check for loose system mounting parts, exposed wiring and other areas of concern. Avoid doing that on your own to maintain your warranty.
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How net metering works?

Net energy metering (also referred to as NEM) is a billing mechanism, which allows a customer to store the electric energy in the electric grid operated and controlled by the electricity supplier. This stored energy originates from a consumer's ability to generate energy by the means of renewable energy sources solar and wind. Then, the NEM lets the particular household benefit from the fact that some of their energy was not used at the time of its production and sent to the grid's infrastructure instead.

To check how it works in the case of solar energy, see the article below:
What is net metering in solar energy?

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